Method of Making Faux Stainless Steel Finish on Bare Carbon Steel Substrate

ABSTRACT

A faux stainless steel sheet material of ferrous carbon sheet steel core is polished in a polishing apparatus comprising a series of commercially available polishing heads each of which utilizes a polishing belt of a predetermined grit mesh and size, belt speed, belt oscillations transverse to the sheet steel conveyed direction, at predetermined conveyance rate of the sheet steel and pressure. The polishing heads scratch the material surface wherein the scratches mimic a stainless steel finish such as #4 stainless steel finish (80 mesh). An example and sample are described in one embodiment of the invention.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of copending U.S.application Ser. No. 12/417,803, the entirety of which is herebyincorporated by reference, filed Apr. 3, 2009, which claims the benefitof provisional applications Ser. Nos. 61/052,338 filed May 12, 2008 and61/101,728 filed Oct. 1, 2008 the entirety of both of which are herebyincorporated by reference.

This invention relates to a method for providing a finish to the surfaceof a carbon ferrous sheet steel substrate that visually appears to bestainless steel and a method of making.

Of interest is U.S. application Ser. No. 11/221,300 entitled FauxStainless Steel filed Sep. 7, 2005 assigned to the assignee of thepresent invention and also to ISG (International Steel Group).

Currently stainless steel for architectural applications, medicalequipment, food industry equipment, vehicles, sanitary equipment,household appliances and so on is in wide use. Such finishes forhousehold appliances and so on such as refrigerators, dishwashers,washing machines, ovens and the like are becoming popular and also arebecoming widespread in use. Other finishes for such appliances typicallyare enameled and in some cases are finished in front with simulated woodgrain panels and the like. Such finishes typically include enamel orother paint like finishes, which are less costly than stainless steeland are in wide use. One type of finish is a relatively low cost plasticlaminate that simulates stainless steel for home appliance use. Theproblem with stainless steel material for such uses is its relativelyhigher cost.

Carbon steel sheet presently may be polished and provided with a coatingto protect it from corrosion. The carbon ferrous sheet steel may be aniron substrate with carbon added. The coating on the polished sheetsteel may be a clear polymer or a metal coating, sometimes referred toas galvanized, or a combination thereof, as commercially available toprotect the steel sheet from corrosion. Such carbon steel coatings mayinclude zinc and aluminum, or zinc, aluminum, silicon, iron and titaniumor zinc and nickel alloys. The metal coating is then finished with aclear coating. The clear coating is a polymer and protects the coatedfinish. This coated sheet material is less costly than stainless steel,but does not have the same high quality look and appearance of stainlesssteel.

The above-noted copending application discloses a carbon steel or otherbase material, preferably metal, but whether or not steel, that hasmetal coating as described above that is polished to simulate astainless steel finish, but not the cost. The coating is polished withone or more grit belts and the polished material is then coated with theclear polymer coating. Such a non-stainless steel metal finished productis intended to provide lower cost, but provide a quality appearance tovarious consumer goods such as the appliances and other goods asdescribed above. However, the present applicants recognize a need foreven lower cost simulated stainless steel product wherein the metalcoating is eliminated. It is not known in the metals industry thatconventional sheet carbon steel can or could be finished to have theappearance of stainless steel. This gives rise to the need in the priorart to provide a metal coating of the types described above which wasthen polished to simulate the SS finish.

U.S. Pat. No. 7,125,613 to Tullis et al. also describes a polished metalcoated ferrous CRS substrate, having a metal coating of Zn—Ni alloysimilar to those described in the above noted copending application andwhich is further protected with a PVC, polyester, acrylic or epoxycoating.

U.S. Pat. No. 6,440,582 to McDevitt discloses an abraded polished finishon a coated CRS ferrous substrate that is intended to simulate stainlesssteel. The coating is abraded by abrasive brushes. However, thismaterial was not commercially successful as the finish that was producedby the abrasive brushes was not commercially reproducible as asatisfactory replica of stainless steel.

U.S. Pat. No. 5,049,443 to Kuszaj et al. discloses a steel multi-layeredcomposite molded structure. This is disclosed as a plastic backedenameled carbon steel or stainless steel finish product that has highimpact, delamination and thermal shock resistance. The composite isformed of carbon steel or stainless steel and thus does not solve theproblem noted above when using stainless steel. The carbon steel orstainless steel has a finish side of a shell layer of reinforced plasticbonded directly to the steel using silane to form a laminated structure.This patent is not directed to providing a substitute for the morecostly stainless steel material and in fact may use such material in itsstructure.

U.S. Pat. No. 6,770,384 to Chen discloses an article coated with amulti-layer decorative and protective coating having the appearance ofstainless steel. The coating comprises a polymer basecoat layer on thesurface of the article and vapor deposited at a relatively low pressureon the polymer layer. A protective and decorative color layer comprisesthe reaction products of refractory metal or refractory metal alloy,nitrogen and oxygen wherein the nitrogen and oxygen content of thereaction products are each from about 4 to about 32 atomic percent withthe nitrogen content being at least about 3 atomic per cent.

US Publ. No. 2005/0040138 to Sato et al. discloses a surface finishingprocess for stainless steel where beautiful, bright and milky whitecolored surfaces are obtained for high carbon-containing 13 chromiumsteel and high sulfur-containing free cutting stainless steel. Thesurface is descaled first and then immersed into treating solutions.This process thus enhances stainless steel, but does not provide asubstitute material that looks like stainless steel but does not haveits cost.

U.S. Pat. No. 6,203,403 to Odstrcil et al. discloses a method forpolishing stainless steel laminate press plates to produce anondirectional, high gloss surface. This patent is not relevant to theproblem of providing a low cost material that appears to have the finishof stainless steel.

a ferrous carbon steel sheet material substrate; and

A faux polished stainless steel sheet according to an embodiment of thepresent invention comprises a carbon ferrous sheet steel substrate, andan abrasive particle grit polished finish on the exterior surface of thesheet steel substrate, which finish simulates polished stainless steel.

In one embodiment, a protective coating is on the sheet steel substratewhich coating permits the polished surface to be visible.

In a further embodiment, the polished surface has a roughness in therange of 10-20 RA, scratches having a length of about 9.54 to 12.7 mm (⅜to ½ inches) and a reflectivity of about 80 to about 115 gloss unitsacross the scratches and about 100 to about 170 gloss units parallel tothe scratches gloss units, where a gloss unit is the ratio of lightspecularly reflected to the total light reflected wherein specularlyreflected light is one wherein the angle of incidence equals the angleof reflection.

In a further embodiment, the polished surface has a reflectivity in arange of about 80 to about 115 gloss units across the scratches andabout 100 to about 170 gloss units parallel to the scratches gloss unitswherein a gloss unit is the ratio of light specularly reflected to thetotal light reflected wherein specularly reflected light is one whereinthe angle of incidence equals the angle of reflection.

Preferably, the surface has scratches having a length of about 9.54 to12.7 mm (about ⅜ to ½ inches).

In a further embodiment, the polished grit abraded surface of the carbonsteel substrate has a surface roughness in the range of 10-20 RA.

In a further embodiment, the polished carbon steel substrate finish hasthe appearance of a commercially defined abraded stainless steel finishcomprising 80 mesh wherein the term mesh refers to an abrasive polishingbelt grit value.

A method of producing a faux stainless steel sheet according to anembodiment of the present invention comprises polishing a carbon ferroussheet steel substrate to produce a surface finish with an abrasiveparticle grit to mimic a stainless steel finish.

In one embodiment the polished sheet substrate is coated with aprotective coating such as a polymer or the like wherein the polishedstainless steel finish is visible through the coating.

In a further embodiment, the polishing step comprises forming scratchesin the surface with scratches having a length of about 9.5 to 12.7 mm(about ⅜ to ½ inch).

In a still further embodiment, the polishing step comprises polishingthe surface to a reflectivity in the range of about about 80 to about115 gloss units across the scratches and about 100 to about 170 glossunits parallel to the scratches gloss units wherein a gloss unit is theratio of light specularly reflected to the total light reflected whereinspecularly reflected light is one wherein the angle of incidence equalsthe angle of reflection.

In a further embodiment, the polishing step comprises engaging a Sicarbide particle loaded grit belt with the surface in transverseoscillations having an amplitude of about 6.35 mm (¼ inch) at 45 cyclesper minute and at a sheet material feed rate of about 25.908-32 m/min(85-105 f/min).

In a further embodiment, the polishing comprises forming an appearanceof a commercially defined abraded polished stainless steel finish with aSi carbide particle loaded grit belt comprising about 80 mesh whereinthe term mesh refers to the belt grit value.

In a further embodiment, the method comprises providing the surface witha surface roughness of about 10-20 RA.

In a further embodiment, the polishing includes coating the polishedsubstrate with a polymer coating to protect the underlying substratefrom corrosion wherein the polished finish is visible through thecoating.

In a further embodiment, the method comprises forming the substrate atabout 0.635 mm (0.025 Inches) thick.

In a further embodiment, the polishing step comprises removing up toabout 0.0127 mm (0.0005 inches) of material from the substratethickness.

IN THE DRAWING

FIGS. 1 a and 1 b together form a schematic diagram of a polishing lineof a coil to coil polisher apparatus for polishing coiled sheet metal,FIG. 1 b being a continuation of FIG. 1 a at regions I-I;

FIG. 1 c is a fragmented sectional elevation view of a polymer coatedcarbon ferrous sheet steel substrate after polishing;

FIG. 2 is a more detailed elevation view of a representative polishinghead using a two roll polishing configuration employed in the polishingline of FIGS. 1 a and 1 b;

FIG. 3 is a fragmented side elevation view of a contact roll used in theapparatus of FIGS. 1 a and 1 b;

FIGS. 4 a and 4 b are graphs useful for explaining certain principals ofthe present invention;

FIG. 5 is a 50× magnification photograph illustrating the grindinggrooves produced on the substrate on the left, center and right sideportions of the polished surface of the bare carbon steel substratepolished to simulate stainless steel wherein the length dimension of thecoil of the substrate extends from the drawing bottom to the top of thefigure;

FIG. 6 illustrates a top plan diagrammatic view of a sample of thecarbon steel substrate (referred in this art as mild steel) 12.25 inches(31.1 cm) by 12.25 inches (31.1 cm) divided into 9 sections and referredto in the graphs of certain of the figures;

FIG. 7 is a graph illustrating the total, diffused and specularreflections across the polished face of the carbon steel substrate;

FIG. 8 is a graph illustrating the total reflection at differentsections of the polished face of the carbon steel substrate of FIG. 6;

FIG. 9 is a graph illustrating the diffused reflection at differentsections of the polished face of the carbon steel substrate of FIG. 6;

FIG. 10 is a graph illustrating the specular reflection at differentsections of the polished face of the carbon steel substrate of FIG. 6;

FIG. 11 is a graph illustrating the average total, diffused and specularreflectivity at different sections of the polished face of the carbonsteel substrate;

FIG. 12 illustrates a chart manifesting the standard deviation fortotal, diffused, and specular reflectivity of the carbon steelsubstrate;

FIG. 13 is a graph illustrating the average total reflectance of thepolished face of the carbon steel substrate as compared to stainlesssteel;

FIG. 14 is a graph illustrating the average diffused reflectance of thepolished face of the carbon steel substrate as compared to stainlesssteel;

FIG. 15 is a graph illustrating the average specular reflectance of thepolished face of the carbon steel substrate as compared to stainlesssteel;

FIG. 16 is a graph illustrating the diffused total reflectivity of thepolished face of the carbon steel substrate as compared to stainlesssteel;

FIG. 17 is a graph illustrating the specular reflectivity as a % of thetotal reflectivity of the polished face of the carbon steel substrate;

FIG. 18 is a photograph at 500× magnification of the cross section ofthe stainless steel sample referred to in the various other figures;

FIG. 19 is a top plan view of the polished stainless steel samplereferred to in the various other figures; and

FIG. 20 is a is a graph illustrating the total and specular reflectanceof the polished face of the stainless steel sample referred to in thevarious other figures;

DEFINITIONS

AP—After polish

Belt—A commercially available polyester backing to which an abrasivegrit has adhered. Size of belt (width) is not a factor in polishingmetals.

Billy roll—A steel roll directly beneath and supporting the sheet steelbeing processed.

BP—Before polish

Color—The visual subjective appearance of the finish and through a clearcoating applied over the faux SS polished material.

Coolant—A water soluble liquid applied to the belt at the polishingarea. May have a minor effect on color of the finish. Coolant reducesfriction from the abrasive grit laden belt, adds lubricity andcontributes to a more shiny, reflective surface.

Finish—The final condition of a surface after the last phase ofproduction. A rougher finish generally means a more dull, grayishappearance on stainless steel as may be produced by a more aggressivegrit such as aluminum oxide or zirconium as compared to siliconecarbide. An aggressive finish, i.e., rougher, may appear to have a moresilvery gray “wild” appearance due to its rougher condition and a lessaggressive finish produced by smaller grit, e.g., silicone carbide, mayappear to have a softer satiny darker finish. A smoother surface will bemore reflective than a rougher surface.

#1 to #5 finish—A conventional finish applied to stainless steel (SS) asaccepted as an industry wide standard.

#3 Finish—100 mesh intermediate used where a semifinished polishedsurface is sufficient as further finishing operations will followfabrication.

#4 Finish—120-150 mesh applied to a preconditioned sheet using abrasivebelts and lubricating oils. A uniform commercial finish used extensivelyin food, dairy and pharmaceutical process equipment, or anywhere asmooth sanitary appearance is desired. Architectural quality sheets areproduced from suitable starting material with knowledge of end usedetails.

#6 Finish—This is a dull satin finish having lower reflectivity than #4.It is produced by tampico brushing #4 finished sheets in a medium ofabrasive particles and oil. It is used where dull matte finishes arenecessary.

#7 Finish—This has a high degree of reflectivity, produced with fineabrasives to 320 grit then using a heavy lubricant or buff to bring thefinish to a semi-mirror without removing the grit scratches. It is usedchiefly for architectural trim and ornamental purposes or specialindustrial applications where a very fine finish is required.

#8 Finish—This is the most reflective of the AISI/ASM finishes. It isobtained by polishing with successively finer abrasives and buffingextensively with very fine buffing rouges. The surface is essentiallyfree of grit scratches from preliminary grinding. This finish is mostwidely used for architectural applications, press plate mirrors andreflectors.

Finish specifications—Standard finishes provided by ASM/AISAspecifications available at www.ssina.com.

Standard 3A Finish—150-240 grit finish

Sanitary Finish #3—80-100 grit finish, Ra</=40 microinches

Sanitary Finish #4—100-120 grit finish, Ra</=25 microinches

Pharmaceutical Finish #7—Buff Finish (mirror like)

Pharmaceutical Finish #8—Buff Finish (mirror like)

Grit—particles, an abrasive particulate material typically silicone,aluminum oxide or zirconium, applied to a polishing substrate such as aconventional abrasive polishing belt. Expressed in terms of numbers.e.g., 80/120/150/180/220 and so on. The smaller the number the largerthe grain size of the particles and the rougher the surface roughness.An 80 mesh is rougher than a 120 mesh. Representative grits includesilicone carbide, aluminum oxide, and zirconium. Silicone carbide ispreferred for the present invention as it breaks down during use and isnot too aggressive and is used for standard finishing and polishing.Aluminum oxide is used for light grinding and finishing in some cases.Zirconium is used for heavy grinding and stock removal. Suppliers ofsuch grits include the following companies: 3M, Norton, Hermes, VSM andSancap.

Head pressure—Pressure load—Pressure of the polishing belt on the sheetmetal being polished. Measured in terms of % load amperage on the beltdrive motor. The higher amperage, the higher the pressure, the moreaggressive the removal of material. Most motors idle at 20% load andpolish stainless steel at about 75% load.

Head speed—The speed of the belt driven in the head by a drive roller.

Lightness L—Visual perception of the relative color and/or whiteness ofa metal finish on a grayscale of black (0) to white (100).

Mesh—belt grit, e.g., 120-150 grit for silicone carbide grit.

Microinch—Root Mean Square divided by 1.11=one Microinch (oneMicroinch×1.11=RMS)

Polish—Providing an exterior surface finish to metal that changes itsappearance by scratching the surface of the metal with fine grit toprovide an aesthetic pleasing smooth and finished appearance to theexterior surface.

Polishing head—A set of two rolls about which a polishing belt isdriven. One roll is motor driven and the other roll is an idler. Thecontact roll is motor driven and is the belt driver. The other roll isthe idler roll and is used to track the belt and is belt driven.

Ra or RA—Arithmetical average surface roughness. See FIG. 5 a. Roughnessaverage is the arithmetic average height of the roughness irregularitiesmeasured from a mean line within a sample length L. This parameter maybe commonly referred to as “the finish.”

${Ra} = {\frac{1}{N}{\sum\limits_{I = 1}^{N}{Yi}}}$

where Yi is the value of the profile deviations from the mean line overan evaluation length, not the sample length for ANSI

Rq-RMS—Root Mean Square surface roughness. See FIG. 5 b. This is moresensitive to occasional peaks and valleys, making it a more valuablecomplement to Ra. While Ra is the arithmetic average, Rq is thegeometric average height of the roughness component of irregularitiesmeasured from the mean line with the sampling length L. Rq is the squareroot of the arithmetic mean of the squares of profile deviations (Yi)from the mean line.

${Rq} = \left( {\frac{1}{N}{\sum\limits_{I = 1}^{N}{Yi}^{2}}} \right)^{1/2}$

where Yi is the value of the profile deviations from the mean line overan evaluation length, not the sample length for ANSI

Scratch—A linear impression, i.e., a groove, in a surface having adepth, length, width and relative orientation to a substrate length. Notimportant, per se, in defining a finish, which is best determined bysurface roughness Ra or Rq as defined herein and as produced by andmanifested by an array of scratches.

Scattered reflection—The angle of incidence of light differs from theangle of reflection.

Specular reflection—Reflection of light where the angle of incidenceequals the angle of reflection.

SS—Stainless steel

Surface Finish Roughness—Measured in RMS (root mean square) or Ra (orRA) (average surface roughness). RMS is about 11% higher than Ra andtypically is used as a measure of final finish rather than reflectivityto provide a quantified measure of the surface condition. The appearanceof the surface finish to an observer is subjective and its appeal iscorrelated to surface roughness to assure repetitiveness.

Total reflectance—Specular and scattered reflection combined.

In FIGS. 1 a and 1 b, polishing apparatus 10 generally is conventionalutilizing individual apparatuses that are conventional in the metalpolishing art utilizing commercially available polishing belts that haveassociated grits. This however, is notwithstanding the fact that thecombination of polishing belts, and corresponding mesh, belt pressure,speed, grit, time and depth of polishing and related polishing factorsdescribed hereinbelow are novel. The apparatus 10 comprises a pluralityof polishing heads aligned in a linear array.

It is known, however, that every polishing apparatus comprising one ormore polishing heads, even if otherwise identical from the samemanufacturer, may produce a slightly different unique finish for a givenset of variable factors. These factors, however, while being variable,can be adjusted in each apparatus to produce substantially the samefinish. Those variables that exhibit the least influence over finishinclude the type of polishing head, two or four roll, belt size, i.e.,its width, the oscillation parameters of the belt, and the type ofcoolant.

Each of the polishing heads in the apparatus 10 cooperates with each ofthe prior and subsequent heads in a linear sequence to produce thefinished product. This sequence polishes the carbon ferrous steel sheetsubstrate material which is cold rolled steel. This material is ofconventional gauge and width, as used to finish the exterior surfaces ofmajor appliances such as refrigerators, ovens, clothes washers anddryers, dishwashers and others, or may used in vehicles or inarchitectural applications to provide the simulated appearance of SS.

Such appliances or applications fabricated with conventional SS sheetmetal exteriors are relatively costly and popular. It is believed byproviding faux SS with a carbon ferrous sheet steel substrate, which maybe cold rolled steel as in the present embodiment, which is less costlythan ordinary SS, the cost of the related appliances or other productscan be reduced. This makes such appliances or other products availableto a less affluent wider portion of the population.

In FIGS. 1 a and 1 b, the carbon ferrous cold rolled sheet steel 20(CRS) is supplied from a coil 12 located at coil supply and uncoilingstation 14. While coils are described as the form of the sheet material,it may be supplied in other forms, e.g., discreet sheets. Such sheets,which are not preferred for the present polishing embodiment, may betack welded to each other during processing to form a continuous sheet.The coiled sheets are later, after polishing, are cut into discreetsheets (not shown) according to a particular implementation.

Other coils 12′ of carbon steel sheet material await polishing asreplacements for coil 12 in an array 16 on support 19 when the polishingof the coil 12 is completed. The coils 12, 12′ are stacked in a columnin the array 16.

Station 14 is a conventional twin cone uncoiler 18, which uncoils thesheet steel 20 from the coil 12. A conventional arrangement is provided(not shown) which moves a new coil 12′ into the uncoiler 18 at station14 when the current roll 12 being processed is emptied of sheet steel.The sheet steel 20 is then pulled through the remainder of apparatus 10by a coiling station at recoiler 98, FIG. 1 b, at the other end of theapparatus 10 during polishing.

In FIG. 1 a, downstream from the uncoiler 18 is an entry feed table 32including an entry pinch roll 33 and an entry side guide 35. Downstreamfrom the guide 35 is a weld table 34 for performing weld operations onthe sheet material as deemed necessary. For example, the end edge of asheet being processed is tack welded to the leading edge of the next tobe polished coil sheet. Downstream from the weld table is a firstpolishing head 36. This head 36 may include an abrasive polishing belt38, which belt includes an appropriate abrasive mesh attached, and whichcan be used to polish the underside surface 40 of the sheet steel 20 ina bottom surface polishing stage. However, in the present embodimentbelt 38 is not in place or used. The underside of the sheet steel 20 isnot polished in this embodiment.

Apparatus 10, FIGS. 1 b and 2, includes representative first polishinghead 46 having an abrasive polishing belt 48. Down stream from head 46are polishing heads 72, 74 and 76 (not used). The head 46 has a two rollconfiguration as do heads 72, 74 which are substantially the same ashead 46. FIG. 2 shows a more detailed illustration of the two rollconfiguration of representative head 46. The head 46 comprises an upperidler roll 50 and a small diameter lower driver roll 52, referred to asa contact roll in this art, which together drive the abrasive grit ladenbelt 48.

The roll 52, which is representative of other contact rolls used in theapparatus 10, is shown in FIG. 3. The roll 52 is made of rubber, and hasthe parameters noted in Table 2 below. The land in the Table isdimension L, the groove is groove g in FIG. 3, the angle of the groovesto a circumferential direction is a and the depth of the groove g isdimension d_(g). The durometer is the hardness of the material and issignificant in the final finish parameter affected by the roll. Thesignificance of the groove g, its depth d_(g), its angle α and the widthof the land L between the grooves, the roll diameter and its durometeris as follows.

The contact roll 52 is important in the finishing process. The contactroll serves the purpose of causing the coated belt to perform as ifrigid and the abrasive particles on the belt to act as a group of sharpcutting teeth. It is an instrument that makes producing close andprecision tolerances on thin carbon ferrous sheet steel possible. Also,other parameters of the finishing process can influence the finishingprocess performed by the abrasive belts. There may be no optimum contactroll design for any given application. However, a discussion of thecauses and effects provide guidance to select the contact rollparameters is appropriate for the processing of the carbon sheet steelsubstrate material according to an embodiment of the present invention.

Some of the issues involved are whether the process is wet as in thepresent embodiment, or dry. The rate of stock removal, tolerances andfinish requirements also play a part in specifying the contact rollparameters. In a wet process, the type of fluid or water soluble fluid,i.e., the coolant, and the chemical additives are beneficial to insureagainst deterioration and softening of the roll in use. The contactrolls need to be dynamically balanced at the RPM of use to insureminimum vibration or other undesirable results in an unbalanced roll.

Roll hardness is commonly measured by indentor type gauges that arecalibrated in the “A” scale (ASTM D2240 and MIL-T-45186). The range ofthis scale is 0 to 100, with lower numbers (50 and lower) indicating arelatively soft condition and higher numbers (higher than 50) indicatinga relatively hard roll. The durometer tolerance is typically +/−5. Softdurometers are used where stock removal is not of prime concern. Suchrolls will conform to tapered or crowned sheet material without scalpingand are also used to generate fine finishes. Harder durometers are usedfor heavy stock removal and thus are not desirable for the presentprocess, which is directed to removing a minimum amount of material topolish the material to the desired finish.

The land to groove ratio is important to minimize and avoid chatter.Such ratios should not exceed 1:1 to minimize such problems. Grooves arepreferably used to minimize contamination, i.e., oil, dirt etc. If theroll face becomes contaminated, objectionable marking and streaking ofthe roll surface (the land areas) may occur with the use of fine gritbelts. The grooves preferably should be formed with a radius at the rootto provide more support for the individual lands to prevent fatigue andsubsequent premature breakage of the land areas.

The roll groove angle α, FIG. 3, has a possible range of 0 to 90°, butsuch a wide range is not used. The preferred range of the angle α isbetween a minimum value of about 8° and a maximum practical angle ofabout 60°. The 8° value provides a better finish than polishing with the60° angle and is less aggressive. In the present process, however, thegroove has a preferred angle of 45°. The 60° value is the maximumaggressive abrasion that results in a poor finish where that isacceptable and is not used with the present process for obvious reasons.

Any value less than 8°, e.g. 0° is not usable because striping orstreaking occurs in the finish. More than 60°, for example 90°, is notusable because it results in excessive pounding, chatter, vibration andpremature product destruction. The values between 0° and 8° increasesthe striping or streaking so that the finish is undesirable or valuesbetween 60° and 90° results in increased undesirable pounding, chatter,vibration as the value approaches 90°. For the present process, the rollgroove angle is preferred at about 45° as shown in Table 1. As the needfor uniform, mark free finishes increases as in the present embodiment,the angle of the grooves, which form serrations, decreases. No groovesor serrations are used where mainly polishing and fine finish generationis desired using soft 25-50 durometer contact rolls and where stockremoval is minimal. As a result, to finish the steel substrate asdescribed herein, a 50 durometer contact roll is used.

Contact rolls may be urethane as well as rubber compounds. A rubbercompound is preferred for the contact rolls for the present apparatus10. Hardness can range from 25 Shore A durometer (very soft) to 95 shoreA durometer (very hard). The preferred durometer in the present processis shore A 50. The preferred grit is silicone particles. The contactroll among other factors in the process are described further in Table 1below.

The belt 48, as all of the polishing belts used in the apparatus 10polishing heads, three heads of the type shown in FIG. 2 being used in alinear array as in FIGS. 1 a, 1 b, has a width normal to the drawingfigure of about 1.57 m (about 62 inches) whereas the sheet steel 20substrate has a width of about or less than 1.22 m (48 inches). Directlybeneath the lower roll 52 and beneath the sheet steel 20 being processedis a support billy roll 54. The relative vertical position of roll 54 isadjusted by a crank (not shown) to apply the pressure to the roll 52,the belt 48 and to the sheet steel 20 between the two rolls 52, 54during polishing.

The head pressure is measured as a function of the load amperes drawn bythe drive motor in the head. See Table 1 for exemplary pressures in theexample shown. Roll 54 supports the sheet steel 20 as it is conveyedthrough the station 46 as well as applies pressure. Abrasive belt 48,laden preferably with silicone abrasive grit, but could be grit of othermaterial as well, is driven by roll 50 via a motor (not shown).

In addition, an oscillating mechanism (not shown) oscillates, by apivoting action, the upper drive roll 50 to displace the belt 48 at thedrive and belt tracking roll 52. The roll 50 and the belt 48 aredisplaced in a direction normal to the feed direction 58 of the sheetsteel 20 in and out of the drawing sheet perpendicular to the drawingsheet. The upper roll 50 is oscillated to thus reciprocate the belt 48in directions normal to directions 58 in a range of about 0.635 cm toabout 2.54 cm (about ¼ inch to about 1 inch). In this embodiment asshown in Table 1, the oscillation of roll 50 and the belt 48 normal tothe drawing figure is about 0.635 cm (¼ inch). This motion transfersoscillating transverse motion amplitude to the belt 48 passing about thedriven contact roll 52 of about 0.635 cm (¼ inch) in the directionnormal to direction 58 for this embodiment. For other steel materialsthis value may have different values. Thus as the sheet steel 20 ispulled in direction 58, the belt 48 is oscillating in a normal directionat its sheet steel 20 contact region at the above noted 0.635 cm (¼inch) amplitude. The values of grit size, belt speed, contact rollpressure, feed rate of the sheet material determine the finishcharacteristics on the sheet steel surface 26″, FIG. 1 c, in cooperationwith the downstream steps described below and in Table 1. However, thevariables that have the most effect on the finish are the type of belt(the grit) and head pressure. Too much pressure or a too aggressive beltcan readily polish too much substrate material. The oscillation periodis one of the factors including line speed in direction 58 that sets thescratch lengths of the scratches produced on the sheet steel 20 by theparticular abrasive grit on the belt 48.

Lighter gauge sheet material is run through the apparatus at a higherrate than thicker gauges. Heat is built up by the polishing process.Such heat can warp the sheet steel by inducing center buckling or edgewaves. A coolant can prevent this action, but too much dwell of thesteel sheet material at the belt, based on line speed in direction 58,FIG. 2, can pose a risk of too much material removal. This result of toomuch material removal is much more prevalent when run polishing isperformed without a coolant. The final result can be achieved by trialand error within the skill of those of ordinary skill in this art. It ispossible to run both thicker and thinner gauges at the same speedthrough the apparatus by careful attention to the parameters to providea given appearance of the faux SS finish.

Belt widths for sheet steel of 48 inch widths or smaller may be 52inches. In this embodiment, however, polishing belts of 62 inch widthare employed. See Table 1. The length of a belt (Table 1) is a functionof the number of rolls and their spacing in a given head. A belttypically has a seam diagonally across the belt width. This seam isnon-parallel to and transverse a maximum amount to the contact roll 52grooves g, FIG. 3, to preclude belt damage during operation.

The faster the line speed, i.e., the speed at which the sheet steel 20is pulled by the take up recoiler 98 in direction 58, FIG. 1 b, thelonger the scratch, i.e., the longer the section of the sheet steel thatis contact with the grits as it passes beneath the contact roll for agiven oscillation period of the roll 50. The faster the head speed theshorter the scratch. The faster the oscillations of the belt, theshorter the scratch. The oscillations determine and thus providescratches of limited length. Otherwise, without the oscillations, thescratches would be continuous and not desirable.

An adjustment apparatus (not shown) in head 46, FIG. 2, which isconventional as is the head 46 in general, adjusts the vertical positionof the lower support roll 54 toward and away from the sheet steel 20.This applies the pressure of the conveyed substrate sheet steel 20against the belt 48 at the position of the contact roll 52. The lowersupport roll 54 is referred to in this art as a “billy roll.” The amountof pressure on the belt 48 is measured by and setting the currentamperage value drawn by the drive motor (not shown) for roll 50 drivemotor. The current amperage drawn by the drive motors for the driverolls such as roll 50 is correlated to pressure. Generally, acorrelation table may be utilized to correlate drive motor amperage topressure of the belt on the conveyed substrate being polished, theferrous carbon sheet steel 20.

Different polishing lines may be set up with different polishing headsaccording to a particular steel composition and/or surface condition,i.e., surface roughness or defects, presence of rust etc. Thesepolishing heads may be set up with different factors as discussed belowin connection with Table 1. One set of polishing heads may be used forone finish and one steel composition and another set of polishing headsmay be used for a different finish on a second different steelcomposition and so on.

The amplitude and frequency of the oscillations of the roll 50 of headis also settable by controls (not shown) and which controls areconventional. The belt 48, FIG. 2, oscillates at the oscillation rate(45 cycles/min) as detailed in Table 1.

Not shown in the figures is a coolant supply apparatus which suppliescoolant to the belt at each polishing head before, at and after thepolishing. The supply apparatus is conventional as supplied by themanufacturer of this machine. The coolant floods the polishing regionbetween the belt and the sheet steel 20. The coolant may be CastrolSyntilo 9730, a product of Castrol company for a synthetic cutting fluidas used in the metal cutting art. The fluid comprises ethanol2,2′,2″-nitrilotris (10-15% by weight), 1-propanol, 2-amino-2methylborax (5-10% by weight) and 1,2-ethanediamine (0.1-1% by weight).An alternative coolant may be 4278 Chemtool, a product of the Chemtoolcompany. This is a synthetic metal cutting fluid comprising ethanol2,2′,2″-nitrilotris (10-15% by weight), hexanoic acid, 3,5,5-trimethy(5-10% by weight) and ethanol, 2-amino (1-5% by weight).

The apparatus 10, FIGS. 1 a and 1 b, includes three roll polishing heads46, 72 and 74 of the representative type shown in FIG. 2. Some of thepolishing heads such as heads 36, 42 and 76 depicted in FIGS. 1 a and 1b are not in use in the present finishing process, but may be used infuture or for other different processes, not described herein, employingthe principles of the present invention.

In FIG. 1 b, further two roll polishing heads 72 and 74, identical tohead 46 are downstream from head 46. A further head 76 is similar toheads 46, 72 and 74 (not used in the present embodiment) is downstreamfrom head 72. Head 76 has a relatively small drive roll 78 and a largerdiameter contact roll 80.

Immediately downstream from head 76 is a conventional hot water rinsestation 82. This station is followed by a drying station 84 for dryingthe sheet steel 20 being processed and followed downstream by an exitpinch roll 86. This is followed by an exit cropping shear station 88 andassociated scrap buggy 90. Next in the line is an optional edge guide 92and a turn roll 94 which deflects the sheet steel 20 to provide tensionon the sheet steel 20 and exit feed table 96. These are followed by therecoiler 98 for coiling the processed sheet steel 20, a coil car 100 forreceiving the coil of polished steel 20 and a kraft protective paperunwind unit 102.

The paper of unit 102 is impregnated to protect the sheet steelsubstrate. In one embodiment, the paper is called Uniwrap® a registeredtrademark of Daubed Cromwell LLC LTD of Burr Ridge, Ill. USA, for anatural kraft paper saturated with Daubed Cromwell MPI volatilecorrosion inhibitor (VCI) formulation. This paper is for protectingferrous/non-ferrous metals combinations including cadmium and zincgalvanized steel. This paper protects the steel substrate from moistureand other environmental elements.

The protective paper of unit 102 is interleaved with the coiled finishedsheet steel 20 for protecting the polished finish surface and the sheetmaterial from corrosion. The protective paper is also wrapped as ashroud about the finished coil.

The polished finished surface is later permanently protected by a clearor tinted polymer coating applied to the finished carbon steel substratesurfaces. The coiled finished material is shipped to this other facilityfor the polymer coating process.

In FIG. 1 c, the clear, i.e., transparent or substantially transparent,protective coating 30, preferably a polymer in this embodiment, isapplied over both sides of the sheet metal carbon ferrous steelsubstrate 22 and completely coats the sheet material on all surfaces.The polymer coating is sufficiently transparent so that the polishedfinish is visible through the coating, and for example, may be tinted toprovide different colors such as bronze, silver and other coloringeffects and so on to the polished material. The coating also may betranslucent if desired. The coating 30 is applied by differentcommercially available independently operated manufacturing facilityspecializing in applying such coatings to sheet steel substratestypically to protect the substrate from the environment and to precludecorrosion.

The clear or tinted coating protects the metal sheet steel substrate andthe polished finish from scratches, scuffs, fingerprints, and corrosion(carbon steel since it includes a ferrous material and thus containsiron, normally will rust unless otherwise protected).

If a conventional SS substrate finish is not acceptable on the processedSS sheet material, the sheet material can be run through the polishingoperation again as the finish is being applied to the thicker base SSmetal. In the present novel process, the same is also true, since thenovel finish of the present embodiment is applied to a base ferrouscarbon steel substrate. If the finish is not acceptable, the finish canbe reapplied in one or more further passes as noted in Table I. Suchmultiple passes may not be desirable for certain substrates in someimplementations where the thickness of the substrate material iscritical. Such multiple passes might thus reduce the thickness to avalue that is not acceptable, since the polishing operation of each passremoves a certain amount of the substrate material. In the presentembodiment, the substrate thickness is reduced no more than about 0.0127mm (0.0005 inches).

This is to be distinguished from the prior art wherein a separate metalcoating is polished as shown in the copending application Ser. No.11/221,300 noted in the introductory portion and in the McDevitt U.S.Pat. No. 6,440,582 also noted in the introductory portion. Such acoating limits the amount of material that can be removed beforeexposing the underlying substrate in an undesirable manner. Such acoating also is much softer than bare carbon cold rolled steel thusrequiring substantively different polishing parameters than that of bareCRS carbon substrate as disclosed herein. In that case, there may not beenough coating material left to redo the finishing process requiringanother coating to be applied, which is costly and defeats the purposeof providing a low cost faux SS finish.

In any case, the back side of the sheet steel 20 substrate, which is notnormally polished, can be used to polish the same coil of steelsubstrate. This is normally is not necessary with a ferrous carbon steelsubstrate since the material is homogeneous throughout. Thus there is noneed to process the otherwise unfinished back side of the sheetmaterial.

TABLE 1 (EXAMPLE) Processing Parameters for polishing a bare ferrouscarbon steel substrate to a simulate SS finish: Substrate 0.635 mm(0.025 inches) thickness Polishing heads Hill Acme Two roll FIG. 2Polishing belt 1^(st) head VSM* 981X or Sancap* C786 60 grit Si Carbide(S/C) Belt 2^(nd) head R468 Norton* 80 grit S/C Belt 3^(rd) head R468Norton* 80 grit S/C belt size 1^(st) head 24.41 cm × 49.6 cm (62 inch ×126 inch) belt size 2^(nd) head 24.41 cm × 49.6 cm (62 inch × 126 inch)belt size 3^(rd) head 24.41 cm × 49.6 cm (62 inch × 126 inch) line speed25.908-32 m/min (85-105 f/min) number of passes** 2 Head Speed RPM1^(st) head 1650 (3887 SFPM) labeled #1 in FIG. 1b (surface feet permin) Head Speed RPM 2^(nd) head 1650 (3887 SFPM) labeled #2 in FIG. 1b(surface feet per min) Head Speed RPM 3^(rd) head 1650 (3887 SFPM)labeled #3 in FIG. 1b (surface feet per min) Head 1^(st) head 65-75 ampsPressure Amperage Head Pressure 2^(nd) head 65-75 amps Amperage HeadPressure 3^(rd) head 65-75 amps Amperage Oscillation stroke length 0.250inches (6.35 mm) (all heads) Oscillation stroke rate 45 cycles/min (allheads) Coolant Castrol Syntilo 9730 Contact Rolls Roll Outside Diameter21.9 cm (8 5/8 inches) 52 FIG. 2 (OD) Durometer 50 +/− 5 Land 12.7 mm(0.5 inches) Groove   9.53 mm (0.375 inches) radius bottom Degree of cut45° left hand helix *manufacturer of head **When the coiled sheet carbonsteel substrate is received from the steel mill manufacturing facility,it is coated in oil by the mill to protect the metal from corrosion.During the polishing operation, the grit belts are loaded with abrasiveparticles. The particles may become clogged due to the presence of theoil and may not function properly. This belt clogging prematurelyrequires one or more of the belts to be changed. When the belts on atleast one head needs to be changed, the process msut be stopped. When abelt is stopped to replace the defective belt, all three heads arestopped, creating unacceptable marks or defects on the sheet material ateach hand.

As a result, to remove these defects requires a second pass of the sheetsubstrate material through the entire apparatus of FIGS. 1 a and 1 b.The coolant does not create a clogging problem. Therefore, the substratesheet steel material is run again in one further and complete passthrough the process to remove the defects, but without the oil presenton the finished surface. If the clogged belt condition does not occurduring the initial pass through the process, a further polishing steppass is not required. When the clogging occurs in at least one beltrequiring the belt to be changed, then two passes are required toproduce an acceptable finish as was done with the example of Table 1.

When the polishing of the sheet material is completed, the material iswrapped in a corrosion protective impregnated paper interleaved with thesheet material. This occurs at recoiler 98, FIG. 1 b, as the material iswound up into the finished product coil at the end of the process.

Characteristics of Surface Finishes of Sheet Metal

Surface roughness—Measured with a profilometer and measures roughnessaverage (Ra or RA). A reading of 45 or above may be considered rough andanything less is considered smooth. The lower the reading the smootherthe finish.

Length of scratch—This is the average length of the scratch polishedinto the surface by an abrasive belt. This is typically measuredmanually.

Color—a comparative subjective description of the color of the finish.

Reflectivity—This measurement is not typically used for polishedfinishes because these finishes are generally not reflective (as inmirror finishes), but are more muted. Reflectivity is measured for thedisclosed embodiment to assist in quantifying the finish. Areflectometer instrument measures reflectivity in gloss units (glossunits reflected into the instrument by the surface in question.). Areading of 500 gloss units or greater may be considered reflective whereany value less than 500 gloss units might be termed muted. A glassmirror measures 1000 gloss units. Correlation of reflectivity to scratchlength or scratch orientation is not known, but is measured herein.Scratch length or scratch orientation is intended herein to onlyquantify the mechanical finish characteristics associated with the fauxcoated stainless steel desired finish.

See Table 2 as follows for finish characteristic factors.

TABLE 2 Parameters which effect the final finish characteristics. 1.Surface roughness (RA)-Belt type, belt grit, contact roll and headpressure 2. Length of Scratch-Line speed, head speed and oscillation ofthe belt 3. Color-coolant, belt type and belt grit 4. Reflectivity-Belttype, belt grit, contact roll, head pressure and coolant

The following Table 3 illustrates the quantifying of the values of Table2 to provide approximate values.

TABLE 3 Surface Roughness (Ra) 10-20 Length of Scratch 9.53 to 12.7 mm(3/8-1/2 inch) Color & visual Dark stainless-like finish, tight grainpattern, appearance(by eye) uniform, scratches visible, shiny scratchesReflectivity (gloss units) See tables 9-12

The preferred finish applied to the ferrous carbon sheet steel 20substrate may be about 80 mesh stainless steel finish. The finish can bedifferent than this and provided in any desired industry standard SSfinishes for which ASM/AISI specifications are written. See theintroductory portion for further explanations of these finishes and alsoto the finishes described in the referred to Designer Handbook ofSpecial finishes for Stainless Steel at the web site noted in theintroductory portion. This document illustrates a wide variety offinishes that can be applied to stainless steel notwithstanding thestandard finishes described above.

In polishing the sheet steel substrate, all preferred factors as followscontribute to the look of the finish. It should be also understood thatthe final look or appearance may also be affected by the protectivecoating.

Head belt drive roll RPM: 1650 rpm or 3887 SFPM

Grit size: Finishing is 80-120 and grinding with aggressive defectremoval is 24-60 grit.

Feed Rate: 25.908-32 m/min (85-105 feet/min)

Belts: Three top side

Pressure Load: 65 to 75 amperes.

In the above tables, the line speed or material feed rate and headpressure are given in ranges. These ranges are due to the varyingsurface conditions of the raw steel sheet material being finished.Portions of the sheet material, which is supplied in coils of relativelarge lengths in the order of thousands of feet, may have a relatively“rough” surface, which requires increased abrasive belt dwell time toremove the undesirable unusually rough condition. In this case, the linespeed may be slowed to 85 fpm and the pressure amperage raised to 75 toincrease the belt pressure on the sheet material. If the sheet materialexhibits a relatively “smooth” surface, the line speed is reduced to 85fpm and the amperage reduced to 65. Of course if different materialsexhibit different surface roughness these parameters may need furtheradjustment as well to different values than those given. Suchadjustments are within the skill of those of ordinary skill in this art.The following is a description of the carbon steel substrate material:

Composition

The material composition was determined using an optical emissionspectrometer.

TABLE 4 Composition-Corresponds with Grade 1005 carbon steel ElementResults % Spec Min % Spec Max % C 0.05 0.00 0.06 Mn = 0.19 0.00 0.35 P0.005 0.000 0.040 S = 0.007 0.000 0.050 Si 0.02 0.00 NS Cr 0.05 0.00 NSNi 0.05 0.00 NS Mo < 0.04 0.00 NS Cu = 0.05 0.00 NS Al 0.04 0.00 NS FeBalance Balance Balance

Micro Hardness Method

Vickers Micro hardness was measure employing LECO Microhardness TesterLM700. with 25 gf applied load was used. Average of at least 10indentations for stainless and 20 indications for carbon steel.

TABLE 5 Microhardness Sample Stainless Steel Carbon Steel Vickers 212.4 120 St. Dev.  12.11 9.24

Sampling

The most variation in properties one can expect across the surfaceperpendicular to the direction of grinding. The samples approximately12.25″×12.25″ were cut into specimens as shown on FIG. 6. FIG. 5 showsthe grooves created by the polishing process on the carbon steelsubstrate. The process produced grooves may be referred to herein asgrinding marks or scratches interchangeably.

TABLE 6 Grinding (scratches) marks per inch Stain

Sample ML MC MR Average ste

Lines per inch measured 1336 1398 1320 1351 17

across the grinding grooves (2.54 cm) Width μm 20 18 19 19 1

indicates data missing or illegible when filed

Surface Roughness

Equipment: Federal Pocket Surf III. Surface roughness (RA) was anaverage of four measurements for each position for the mild polishedsteel. An estimate of the range thus is about 10-20 RA.

TABLE 7 Sample ML MC MR Average SS Surface Roughness (RA) 17 16 16 16.33Surface Roughness (RA) 16 15 14 15 Surface Roughness (RA) 17 20 17 18Surface Roughness (RA) 13 17 20 16.66 Surface Roughness (RA) 18 17 1516.66 Surface Roughness 16.2 17 16.4 16.5 8.2 (average) (RA) (See FIG. 6for ML, MC and MR terms definitions)

Optical Properties Reflectivity.

All spectra were acquired on a Perkin Elmer Lambda 950ultraviolet-visible spectrophotometer equipped with a Lab Sphere model60MM RSA ASSY integrating sphere. Spectra were acquired from 320 to 860nm and auto corrected to a reference standard provided with the sphereby the manufacturer. Two sample mount configurations are available withthe sphere. Spectra were acquired with the samples mounted normal to theincident radiation, which allows for collection of diffuse reflectanceand with the samples mounted at a small angle off norm for collection ofboth diffuse and specular reflectance. Specular reflectance wasdetermined by difference between these spectra.

Color and Gloss

Color Characteristics, L (lightness) a, b, CIE (white) and yellow (ASTM313) were determined using X-Rite SP68 Sphere Spectrophotometer withdual beam optics system. Sample was placed under the target window ofthe spectrophotometer and three readings were taken and averaged. Theunit was calibrated before each use using a reflection standard.

Following Table exhibits the results for color study on the coatedcarbon steel samples and stainless steel after polishing.

TABLE 8 Color Characteristics Color MC MR ML Average Stainless I L 81.7582.04 82.07 81.95 82.8 A −0.27 −0.12 −0.17 −0.19 +0.15 B I +0.16 +0.19+0.17 +4.63 CIE 58.98 59.55 59.41 59.31 38.18 ASTM E313 (yellow) 0.090.09 0.13 0.10 7.92

Lightness for the polished carbon steel substrate and stainless steelare close. The carbon steel is a little whiter reflecting all wavelengths more evenly.

Reflectance/Gloss

Gardner Micro-Tri-Gloss Meter was employed to determineReflectance/Gloss, Tables 9-12. The measurements were conducted at threedifferent angles 20°, 60° and 85° across the grooves (scratches) Table9. The average of three tests was determined Table 10. The measurementswere conducted at three different angles 20°, 60° and 85° along orparallel to the grooves (scratches) Table 11. The average of three testswas determined Table 12. The light that is directed onto the surface ofthe test specimen is at a defined angle and the reflected light ismeasured photo-electrically. The meter was calibrated before each useusing a calibration standard. Tables 9 and 10 are gloss variations whenmeasured across the grinding grooves (12″×12″-Sample)

TABLE 9 Gloss Units Across the Grinding Grooves Reading Reading ReadingSample Gloss 1 2 3 Average Min Max TL 20° 81.2 81.0 83.6 81.93 81.0 83.660° 103.6 113.8 108.4 108.60 103.6 113.8 85° 62.7 65.6 65.4 64.60 62.765.6 ML 20° 80.0 84.4 81.2 81.90 80.0 84.4 60° 110.4 110.0 113.5 111.30110.0 113.5 85° 65.5 64.4 64.9 64.90 64.4 65.5 BL 20° 83.6 79.8 78.080.50 78.0 83.6 60° 105.7 102.8 104.4 10.43 10.4 105.7 85° 63.2 65.063.3 63.80 63.2 65.0 TC 20° 83.3 80.2 81.7 81.70 80.2 83.3 60° 102.3104.9 105.4 104.20 102.3 105.4 85° 62.0 66.8 66.0 64.93 62.0 66.8 MC 20°82.1 76.9 82.4 80.50 76.9 82.4 60° 108.2 103.4 100.5 104.00 100.5 108.285° 64.4 64.3 64.1 64.30 64.1 64.4 BC 20° 79.8 83.8 81.7 81.80 79.8 83.860° 105.8 105.0 103.7 104.80 103.7 105.8 85° 66.2 65.2 65.8 65.70 65.266.2 TR 20° 83.2 78.6 82.4 81.40 78.6 83.2 60° 102.6 108.9 113.6 108.40102.6 113.6 85° 66.9 69.3 66.7 67.60 66.7 69.3 MR 20° 85.0 84.3 79.783.00 79.7 85.0 60° 113.6 107.9 106.9 109.50 106.9 113.6 85° 67.7 66.465.7 66.60 65.7 67.7 BR 20° 77.1 81.5 82.4 80.30 77.1 82.4 60° 101.8105.5 108.3 105.20 101.8 108.3 85° 64.6 66.2 66.8 65.87 64.6 66.8 SS 20°54.1 48.3 46.4 49.60 46.4 54.1 60° 79.7 83.9 87.6 83.70 79.7 87.6 85°95.9 96.9 95.5 96.10 95.5 96.9 See FIG. 6 for definitions of MC, MR, ML

TABLE 10 Gloss Units Across the Grinding Grooves Average Min Max Std Dev20° 81.5 76.9 85.0 2.25 60° 106.8 100.5 113.8 3.90 85° 65.5 62.0 69.31.52

TABLE 11 Gloss units parallel to the grinding grooves Reading SampleGloss Reading Reading 3 Average Min Max TL 20° 159 161.9 161.7 160.9 1516 60° 0 0 0 0.0 0.0 0.0 85° 108 109.3 101.9 106.4 10 10 ML 20° 156159.1 152.3 155.9 15 15 60° 0 0 0 0.0 0.0 0.0 85° 110 104.9 105.4 106.910 11 BL 20° 151 153.3 158.4 154.4 15 15 60° 0 0 0 0.0 0.0 0.0 85° 101104.5 110.6 105.7 10 11 TC 20° 161 160.5 160.8 160.8 16 16 60° 0 0 0 0.00.0 0.0 85° 110 110.4 110.2 110.2 11 11 MC 20° 149 152.3 159 153.6 14 1560° 0 0 0 0.0 0.0 0.0 85° 109 108.9 110.9 109.7 10 11 BC 20° 157 161.4158.5 159.3 15 16 60° 0 0 0 0.0 0.0 0.0 85° 110 109.3 110.1 109.9 10 11TR 20° 165 160.3 166.9 164.3 16 16 60° 0 0 0 0.0 0.0 0.0 85° 107 103.7101.6 104.2 10 10 MR 20° 159 164.4 165.3 163. 15 16 60° 0 0 0 0.0 0.00.0 85° 110 110.3 109.9 110.2 10 11 BR 20° 158 153.6 156.8 156.3 15 1560° 0 0 0 0.0 0.0 0.0 85° 110 109.2 108.3 109.2 10 11 SS 20° 101 96.194.9 97.6 94. 10 60° 0 0 0 0.0 0.0 0.0 85° 121 122.3 120.5 121.5 12 12

TABLE 12 Average Values Parallel to grinding grooves Average Min Max StdDev 20° 158.72 149.5 166.9 4.47 60° 0.00 0.0 0.0 0.00 85° 108.03 101.6110.9 3.00

The zero reading for 60 deg test indicates that the reflected light for60 degrees of illumination of the base surface does not reach the 60degree reflected light detector located opposite the source in anydetectable amount. As an illustration just for understanding thephenomenon, consider an array of grooves with walls of the grooves at 60degrees to the base surface. Light from the source illuminating basesurface at 60 degrees will be perpendicular to the wall surface. In thiscase, in an ideal situation, all the light that reaches the wall isreflected back to the source. Very little or no light will reach thedetector placed at 60 degrees to the base surface opposite the 60 degreesource.

Total, Diffused and Specular Reflectance Reflectivity (Reflectance)

All spectra were acquired on a Perkin Elmer Lambda 950ultraviolet-visible spectrophotometer equipped with a Lab Sphere model60MM RSA ASSY integrating sphere. Spectra were acquired from 320 to 860nm and auto corrected to a reference standard provided with the sphereby the manufacturer. Two sample mount configurations are available withthe sphere. Spectra were acquired with the samples mounted normal to theincident radiation, which allows for collection of diffuse reflectanceand with the samples mounted at a small angle off norm for collection ofboth diffuse and specular reflectance. Specular reflectance wasdetermined by difference between these spectra.

Diffuse reflection is the reflection of light from an uneven or granularsurface such that an incident ray is seemingly reflected at a number ofangles. It is the complement to specular reflection. If a surface iscompletely non-specular, the reflected light will be evenly spread overthe hemisphere surrounding the surface.

Specular reflection in contrast is the perfect, minor-like reflection oflight (or sometimes other kinds of wave) from a surface, in which lightfrom a single incoming direction is reflected into a single outgoingdirection.

Total, diffused and specular reflectivity for the polished carbon steelsamples were determined and compared to a polished stainless steelsample. The carbon steel side opposite the polished side was notmeasured due to unknown surface conditions that modified the surface.

FIGS. 7-10 show reflectance of the polished carbon steel samples asmeasured, showing total, diffused and specular reflections for thecarbon steel sample and in certain of these figures, for the carbonsteel polished sample (referred to in the drawings as mild steel asknown in the metals art) left, middle and right locations across thesample as per FIG. 6. FIGS. 8-10 are amplifications of the differentline portions of the graph of FIG. 7 to show the results more clearly.

FIG. 11 shows the average total diffused and specular reflectance forthe polished carbon steel samples as measured. It shows totalreflection, diffused reflection and specular reflections left, middleand right location across the sample of FIG. 6.

FIG. 12 shows the standard deviations for total, diffused and specularcomponents of the polished carbon steel sample.

FIG. 13 compares average total reflectance of the polished carbon steelsample with stainless steel. They are comparable in value, but thecarbon steel curve is flatter confirming the color test results thatshow that carbon polished (mild) steel is whiter.

FIGS. 14 and 15 show similar behavior for diffused and specularreflectance and demonstrate close values with specular and diffusedcomponents for stainless steel.

FIG. 16 shows that diffused reflection for stainless steel is a higherfraction of total reflection compared to mild steel. Possible effect ofa higher number of grooves for stainless compared to Mild steel.

FIG. 17 compares the carbon steel polished sample (MsSpf-triangle) tothe stainless steel sample and shows that the carbon steel exhibits ahigher total specular reflection similar to the result shown in FIG. 16.

FIGS. 18 and 19 are respective cross section photographs taken at 500×and top plan view taken at 50×. Compare this figure with FIG. 5 andappear to be similar. FIG. 20 shows the total and specular reflectancefor polished stainless steel.

From the forgoing the following observations can be made.

1. The optical characteristics of the polished surface of the carbonsteel are close to the optical characteristics of the stainless steel.

2. The diffused reflection for stainless comprises a higher portion ofits total reflectivity.

3. The increase in the diffused reflectivity portion increases with thedegree of the polishing of the surface.

4. Increased whiteness of the polished carbon steel compared tostainless steel is caused by the difference in the alloy composition(presence of nickel in stainless)

5. Casual observation of the polished carbon mild steel sample visuallymimics stainless steel

It will occur that modifications may be made to the disclosedembodiments by one of ordinary skill. The disclosed embodiments aregiven by way of example and not limitation. For example, the exemplarydescriptions herein are of the processes used to reproduce a simulatedfaux SS finish on a given composition of a cold rolled ferrous carbonsheet steel.

In addition, abrading processes, not shown or described specificallyherein, but utilizing the apparatus disclosed herein or similarapparatus may be used with grit loaded belts to provide faux standard ornon-standard SS finishes. It is intended that the scope of the inventionbe defined by the following claims appended hereto.

1. A method of producing a faux stainless steel sheet comprisingpolishing a ferrous carbon steel sheet material substrate surface withat least one abrasive particle loaded grit belt to form a surface finishthat simulates a polished stainless steel finish on that surface.
 2. Themethod of claim 1 wherein the polishing step comprises forming scratchesin the surface with scratches having a length of about 9.5 mm (⅜ inch).3. The method of claim 1 wherein the polishing step comprises polishingthe surface to form substantially parallel scratches in the surfacehaving a reflectivity in the range of about 80 to about 115 gloss unitsacross the scratches and about 100 to about 170 gloss units parallel tothe scratches wherein a gloss unit is the ratio of light specularlyreflected to the total light reflected wherein specularly reflectedlight is one wherein the angle of incidence equals the angle ofreflection.
 4. The method of claim 1 wherein the polishing stepcomprises engaging a Si carbide particle loaded grit belt with thesurface in transverse oscillations having an amplitude of about 6.35 mm(¼ inch) at 45 cycles per minute and at a sheet material feed rate ofabout 25.908-32 m/min (85-105 f/min).
 5. The method of claim 1 includingthe step of forming an appearance of a commercially defined abradedpolished stainless steel finish with a Si carbide particle loaded gritbelt comprising about 80 mesh wherein the term mesh refers to the beltgrit value.
 6. The method of claim 1 including providing the surfacewith a surface roughness of about 10-20 RA.
 7. The method of claim 1including coating the polished substrate with a polymer coating toprotect the underlying substrate from corrosion wherein the polishedfinish is visible through the coating.
 8. The method of claim 1including the step of forming the substrate to about 0.635 mm (0.025inches) thick.
 9. The method of claim 1 wherein the polishing stepcomprises removing up to about 0.0127 mm (0.0005 inches) of materialfrom the substrate thickness.
 10. The method of claim 1 wherein thepolishing step comprises coating at least the polished surface with acoating that is sufficiently transparent so that the polished surface isvisible through the coating.